How to expand comp if space larger than preferred size. fill can be
GridBagConstraints.NONE, GridBagConstraints.VERTICAL,
GridBagConstraints.HORIZONTAL, GridBagConstraints.BOTH.

gbc.anchor = anch;

If component doesn't fill the space, tells how it should be aligned. anch can be
one of these GridBagConstraints constants:
CENTER (default), NORTH, SOUTH, NORTHEAST, SOUTHWEST, EAST, WEST, SOUTHEAST, NORTHWEST